plasma2: An advanced plasma fractal pattern generation GIMP plugin1

Plasma2 is a heavily improved version, of an old Gimp plugin, Plasma, by
Stephen Norris. This plugin generates cloud-like structures, known as
"plasma fractals". Brief list of fixes and improvements against the original
Plasma. Several new generator options, including the possibility to generate
original Fracting-like and Norris-like plasmas. It can now generate tileable
images, in a much more efficient than the original Plasma's Make_Seamless.
Can directly map to a gradient, and do gradient remixes, and general speed
improvements.